Ratio of thrust to moving mass determines the load capacity of a linear motor.
Less moving mass means more capacity for external load. In addition, the reaction force
due to moving mass under high acceleration and deceleration will result in considerable
vibration to your machine and may lead to unpredictable resonance. So, a good linear motor
stage must keep its moving mass as small as possible.

Consider if you want to move both axis simultaneous and/or independent

Duty cycle must be kept low to avoid overheating

A good linear motor stage must make its number of moving cables as few as possible to increase longevity